1. Field of the Invention
This invention relates to molded magnetic materials. More specifically, the invention is a molded magnetic article such as a transformer core and a fabrication method therefor.
2. Description of the Related Art
Power transformers typically make use of magnetic cores made from soft magnetic materials, i.e., materials having a magnetization direction that can be easily changed. Geometric shapes for such cores generally include complex geometric shapes that define a closed path, e.g., a hollow square or rectangular "picture frame" shape, a donut shape, etc. The magnetic cores are generally fabricated from magnetic ingots that mold-set into a desired shape using heat and pressure. Current magnetic core fabrication methods require extremely high pressures (e.g., on the order of 250 kilograms per square inch (ksi) in order to achieve acceptable levels of magnetic induction saturation or B.sub.MAX of approximately 13 kilogauss (kG). Such results are best achieved as reported by Speed et al, in "Magnetic Properties of Compressed Powdered Iron", Transaction of American Institute of Electrical Engineers, Volume XL, p. 1321-1359, 1921. However, the application of such high pressures reduces the life of the mold sets thereby raising the production cost of magnetic cores.